Refrigerating-machine.



F. G. KEYES.

REFRIGERATING MACHINE.

APPLICATION FILED APR. 25. I9l7. 1,277,085. Patented Aug. 27, 1918.

Q Il @SSE vwewtoz ffy l "EDSamiransf-1mP@FICEA FREDERICK er. KEYES, or BOSTON, MASSACHUSETTS, AssreNon-'ro NATIONAL Au'ro- MATIC EEEEIGEEATOR COMPANY, A'co'EPoRATIoN 0E NEW JERSEY.

REERIGEEA'rINe-M-ACHINE.

AppIication iiled April 25, 1917. Serial No. 164,354.

To all 'whom t may concern.'

- Be it known that I, FREDERICK G. KEYES, a citizen of the United States,` residing at Boston, in the county of Suffolk and State of Massachusetts, have invented certain new and useful Improvements in Refrigerating- Machines, of which the following is a full, clear, and exact description.

. In order that the invention which I shall herein describe as that for which I am seeking protection by Letters Patent ma be the more readily understood, I may exp ain the construction and mode of operation of a refrigerator of now well known character to which the improvement is applicable.

It may therefore be assumed that this apparatus comprises a distilling chamber or receptacle with provision` for heating and cooling its interior, and that it is connected with a condenser which is also provided with a cooling coil or similar means for lowering its temperature and' with a connection wit a refrigerating chamber. f

If now, a refrigerating material, which for purposes of the case, may be assumed to be composed of water, ammonium nitrate and ammonia be placed in the distilling chamber, and the latter heated, the ammonia vapor will be driven over to the condenser which is cooled for the purpose of condens.- ing this vapor and delivering4 it to the refrigerating chamber.

After the ammonia has been all substantially Athus driven over the cooling of the condenser is stopped and the distilling chamber then cooled, whereby the liquid ammonia, owing to its strong affinity for the ammonium nitrate will again volatilize in the refrigerating chamber and pass back into the distillin chamber and enter into the solution therem contained.

For practical reasons it is not desirable l that the condensation of the ammonia vapor should take place in the refrigeratin cham@ ber, as this involves a lowering of e ciency due to the vtransfer of heat. It is therefore desirable to insert in the path of the vapor from the distilling to .the refrigeratmg chamber, a vcondenser which will liquey the ammonia and deliver it inliquid vform to the refrigerating chamber.

Under ordinary conditions the refrigerat-A ing chamber is maintained at a lower temperature than the condenser, so that the normal tendency, were there no intermediate collectlng chamber, would be for the liqbuefaction totake place in the refrigeratmg chamber rather than in the condenser, but

this -I have overcome by using as the material for the walls of the'refrigerating chamber one'having poor heat conductivity, so that although liquefactionmay start and may contlnue to some extent on the walls of the refrigerating chamberthe transference of the heat thus developed isso delayed.L that the temperature of the inner surface may be materially higher than the outer surface of such walls, and so high infact as to cause the pressure to rise to a point where the condenser will be called upon to condense the vapor and deliver it to the refrigerating chamber with its heat of liquefaction abstracted. f

This Lmay be accomplished by the use of various materials, butas metals only need be consideredfor practical reasons, the'uobje'ct j should be to use a metal of verypoor heat Y when the walls are made of a thickness that will bring about the transfer.

Monel metal has a heat conductivity eighteen times worse than copper, and hence 'would be the most desirable material for necessary delay in heat making the walls o f the refrigerat/ing chami ber. v For'purposes of illustration I have annexed hereto a drawing of a refrigerating apparatus containing features which are.

In this apparatus there is shown a household refrigerator, or refrigerating chamber 2, and the object is to supply this chamber with a refrigerant continuously and autof matically, this being done in the following manner. i

At the right of the diagram is shown a distilling chamber 3, surrounded by an electric heating coil 4, adapted to receive energy at the proper intervals from any suitable source, such as indicated at i. y

In the practical -use of this system a composition of ammonium nitrate, Water and ammonia is placed in the distilling chamber and by the heating action of the energized coil 4, the volatile constituents of the mixture are driven over through pipe Y, containing a check valve 8, through a condenser 9, and into the refuge-rating chamber 2.,

rIhre condenser is provided with the usual Water cooling coils l0, through which, when 'ammonia is passing, a dow of `water is maintained from a source represente by the pipe il, through a controlling Valve f2, yand-a pipe i3, to an outlet le. Y

.he condenser 9 is connected with the refrigerating chamber 2, through pipe l5, carrying at its end any device which will deliver the liqueiied ammonia into chamber Q, and the condenser 9 is preferabiy made of copper and so arranged as to secure prompt cooling of the ammonia which streams through In an apparatus of this kind it is possible to distill the' ammonia atsuch a rate as to cause the inner surface of the refrigerating chamber to rise to a temperature considerably higher than the outside surface. Of course, the Walls of a refrigerating chamber should be adjusted to thickness to secure as economical operation as possible, and at the same time magnify the eifectof the delayed heat transfer as fail as practicable. 'Ihe effecty of Warming the inner surface of the refrigerating chamber by the heat of condensation is to cause the pressure to rise to a point Where ultimately the copper condenser must condense the ammonia, permitting it to iow in liquid forni, Withits heat of liquefaction abstracted, into the refrigerating chamber.,

By this-means, in small refrigerators a certain sacrifice in efficiency may be made, but with the result of simplifying to the maximum extent the apparatus used. In practice I have found, when using iron for the refrigerating chamber that this eiiiciency amounts to about 60%. If a bettermaterial,

such as Monel metal, were used for the purpose, however, the efficiency Would be much higher.

s The transfer of ammonia from the dis- .tilling chamber to the condenser continues in this Way until by the loss of ammonia the temperature of the chamber 3 rises to about 1000 C., at which point of time a circuit is closed through a circuit controller 16 that operates the valve 12 to shut ofi' the water from the condenser and direct its flow through the coils 19 in the distilling chamber. p

This operation is effected by any suitable and Well known means which forms no part of the present invention and hence need not be described in detail.

The valve lever in the movement thus iin-- parted to it, operates the circuit closer l?, and interrupts the circuit through the heating coil 4. rl`he circuit closer` is of any proper construction.

Under the conditions thus established the strong affinity of the aqueous ammonium nitrate left in the distilling chamber, for the ammonia in the refrigerating chamber causes the latter to vpass bach from such chamber through pipe 3?, to the distilling chamber through a check valve 355. its there is a similar valve 8, in the pipe this is the 4only path for the ammonia at this time.

r)The ammonia enters the distiliing chamber 3, when it is absorbed.

As the absorption of the ammonia goes on its level in the refrigerating chamber falls, until it `finally reaches a point at which a float 40 operates through any suitable form of mechanism to actuate the circuit closer 18 and through it the Water valve to shut ofi' Water from the coil 19, in the dis tilling chamber, and directs it through the condenser coil, and at the same time closes the circuit through. the coilrIhis completes the cycle of operationsj My invention is not limited to the :forni transfer through them of the heat imparted by the condensation that takes place thereon.

2. In a refrigerating apparatus of the kind herein described, the combination of a distilling chamber, a refrigerating cham ber and an intermediate condenser connected with the chambers, substantially all of the Walls of the refrigerating chamber being of a met-al which has poor heat conducting properties whereby the temperatureof its inner wall surface raised by the condensaa distilling chamber, aA refrigerating chamtion of vapor thereon will increase the' presber and an intermediate condenser connected 10 sure Within it to a point which Will cause with both chambers, substantially al1 of the the condenser to liquefy the vapor and de- ,Walls of .the refrigerating chamber being -5 liver it in liquid form to said refrigerating composed of Moncl metal.

chamber. -v In testimony whereof I aix my signature.

, 3. lIn a refrigerating apparatus of the kind herein described, the combination of f FREDERICK G. KEYES. 

